Electric alarm.



Patented Jan. 29, 1918.

2 SHEETS-SHEET i.

E. S. TABER.

ELECTRIC ALARM.

AFPLlCATlON FILED MAR. so. 1915.

1 ,254,864; Patented J an. 29, 191&

2 SHEETS-SHEET 2.

UNITED STATES PATENT onFroE- EVERETT S TABER, i" CANTON, MASSACHUSETTS, ASSIGNOR T0 SAMSON ELECTRIC COMPANY, OF CANTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECTRIC ALARM.

Patented J an. 29, 1918.

Application filed March 30, 1915. Serial 170.17,.987.

To all whom, it may concern:

Be it known that I, Evenn'xr S. Tann n,

a citizen or theUnited States, and resident of Canto'mi 'in the county ofNorfolk and 6 State oFMassachnset-ts,have invented cortain new and useful Improvements in Electrio Alarms, of which the following is a specification.

This invention relates to an audible sig' L0 nal for firenlarm and other purposes, and comprising av hell or gong, a hammer, and electro-mcchanicai means for causing the hammer to strike the bell.

The inventionhas for its object first to 'provide improved electro-mechanical ham "met-operating means of simple construe tionpproviding for an effective hammer blow. by the attraction of an armature to the poles of an elcc't'ro'magnet, andfor a quick partial rebound of the hammer either by the a"etion of a spring or by gravity, and the maintenance of the hammer out of contact with the bell after the blow. The invention also has for its object to, provide im 26 proved means for protecting the bell, the

hammer and the hammer-operating mechanismagainst injury by water, dust andinsects.

To these and other related ends the in- 80 vention consists in the improvements-which iI WiII now. proceed tod escribe and claim.

Of the accompanying drawings forming a --part of'this specification: v Figure 1' represents a front elevation of 85 a supporting base'and a cover, inclos1ng the shell, the hammer and: the hammer-operating mechanism hereinafter described;

Fig. 2 represents afront elevation of the base, the hammer, and the hammer-operatingwmechanism, the cover and bell being erem'oved; p

' Fig; 3'represents an edge 'view of the base,

the bell,-the. hammer. and the hammer-operating mechanism, the hammer being retracted and. the cover being shown. in sec- 4 represents a section on line.4 4 of Fig.': 1, "showing the hammer being re- Fig.5 represents a view 'simllar-toLF1g. 4,

etho hammer, being pro j ected v Fig. 6 represents a. View showing the base and cover in section and an edge view o.f the bell and the hammer-operating mechamsm,

the hammer being mainly concealed by the 65 operating mechanism I Fig. 7 represents a fragn'lentary perspective viewjshowmg portions of the'hammer and the operating mechanism;

Fig. 8 represents a fragmentary pcrspective view, showing a. portion of the hamrner detached;

Figs. 9, 10 and 11 represent fragmentary Views, partly in section and partlyin cleva tion, showing different relative positions of the armature and the hammer;

Fig. 12 represents a fragmentary sectional view, illustrating a modification;

Fig. 13 represents asectional viewof the cover detached; and

Fig. 14. ,represents a fragmentary sectional view, showing acover composed of sections, one overlapping the other.

The same referencecharacters indicate. v the same or similar parts in all the views. '75

In the drawings, 12 represents a base having means, such as cars 13, whereby it may be attached to a support. To the haseis attached an clectro-magnct, of which 14, H, are the-helicallywound spools and-15, 15, the poles. Thebase is provided with cars or standards 16 supporting pivot screws 17 in alinement with each other. 18 represents an armature located betweenthe standards 16 and mounted. to oscillateon the pointed inner ends of the pivottscrews 17 from the retracted position shown by Figs. 2, 3, 4,

and 9 to the projected position show-n by Figs. 5, 10 and 1 1, the armature being in the last named position when attracted and'hcld 'by the poles of theelectro-magnet. Ashore shown, .the poles 15 are extended. outwardly from the spools and enter orifices 19 (Figs.

6 and 7) formed for their reception in the armature, 20 represents the head and 21 the Shani:

of a hammer which is fulcrumed to oscillate on an. axispreferably 'formed by unthreaded portions of the "pivot screws 1-7,

the shank 21 beingprovided with op'positcly'IOO projecting angularfulcrum-arms 22 :(Figs. and 8)'.ha-v.ingofl'set ends provided RVltil v sockets 23 (FignS) through which said pivbt screws pass. The arms 22'extend alongone= edge g-oj'f, the armature, andits socketed ends-x105. as;

project ot er opposite ends of the armature, as shown by Fig. 7,

The hammer shank is provided with a lever arm 25 which projects over theinner side of the armature 18, and is so formed and arranged that when the armature is attracted by the magnet it imparts movement to the arm and to the hammer, swinging the barnmer head toward the bell 26, which is supported in suitable relation to the hammer, preferably by a bracket 27 attached to the base. The lever arm 25 is held in yielding contact with the armature either by a spring 28 or by gravity, as hereinafter described.

The relative arrangement of the armature. the bell, the lever arm 25, and the hammer is such that when the armature is in its attracted position and the lever arm is in contact with the armature, the hammer head is slightly separated or retracted from the bell as shown by Fig. 11. The lever-arm 25 has a greater amplitude of movement than the armature so that when the armature moves from the position shown by Fig. 9 to that shown by Fig. 10, the movement imparted by it to the arm 25 and to the hammer is continued by the momentum of the hammer, until the hammer head strikes the bell, the arm 25 being at this moment separated from the armature, as shown by Fig. 10. The hammer is therefore free to rebound to the position shown by'Fig. 11 and separate its head from the bell, so that the vibrations of the bell are not muiiied by the hammer.

In the embodiment of the invention shown by Figs, 1 toll inclusive a spring 28 is provided to hold the lever arm 25 yieldingly against the armature. Said spring is interposed between the outer side of the armature and an abutment arm 30 formed on the hammer shank and proiecting over the outer side of the armature, the spring being preferably attached to the armature. The spring is preferred when the base is in a vertical planeand the hammer shank is approxii'nately vertical, but when the base and hammer shank are arranged horizontally,

' the spring and the abutment arm 30 may be omitted, as shown by Fig. 12, the lever arm 25 being held against .the armature by the weight of the hammer.

It will be seen that the alincd pivot screws 17 constitute an axis that is common to the armature and the hammer, and that there is no rubbing or sliding contact between the lever arm 25 and the armature to cause frict onal resistance to the movement of the hammer by the armature, hence the force of the armature, when it is attracted. is fully utilized to impart a forcible striking movement to the hammer.

The'centcr of the bell is preferably opposite the eentral portion of the electro-magnet. as shown, so that the bell, the hammer and the hammcnoperating mechanism constitute a compact group adapted to be protected by a, dome-shaped cover 32. ,Said

cover has cars 33 which are screwed or bolted to the base. The crown of the cover is provided with sound-conducting openings 34 preferably arranged radially, as shown by Figs. 1 and 13. To prevent the admission of dust and insects the said openings are screened with wire cloth 35, or other foraminous material, preferably formed in a single concavo-convex sheet fitting the interior of the cover and extending across the openings. The cover may be provided with beads or flanges 36 surrounding said openings and prO ecting outwardly from the outer surface of the cover to prevent water from rain and snow, and trickling from the upper surface of the cover, from entering the openings. The screening material may be of sufficiently fine mesh to prevent any objectionable entrance of rain or snow into the easing.

The cover may be composed of sections 32 and 32, as shown by Fig 14, the lower edge of the upper section overlapping the upper edge of the lower section to shed water flowing downwardly from the upper surface of the cover. The openings 34 may be formed only in the lower section, the upper section constituting an overhanging closed roof.

Having described my invention, I claim:

1. An electric alarm comprising a. bell, an electro-magnet, an oscillatory armature for said magnet. and an oscillatory bell hammer substantially coaxial with. said armature and provided with a. lever arm which is permanently out of circuit and movable ,by the armature when the latter is attracted,

said arm being normally held in yielding contact with the armature and separable therefrom by the momentum of the ham Iner, so that the arm has oscillatory movements of greater amplitude than those of. the armature. whereby, when the armature is attracted, the hammeris first projected against the bell and is then slightly retracted therefrom. M

2. An electric alarm comprising a bell, an electro-magnet, an armature for said magnet, a bell hammer, means oscillativel supporting said armature and hammer with their axes of oscillation substantially in alinement, and an arm on the hammer arranged to be moved forward-"by the armature when the latter is attracted, said arm being permanently out of circuit, means being provided for yieldingly holding the said arm against the armature and permitting an additional forward movement of the arm by the momentum of the hammer after the forward movement of the armature is atrested, said additional movement projecting the hammer against the bell and being followed by a slight retracting movement.

3. An electric alarm comprising a bell, an electro-magnet, an armature for Sai 

